A randomized clinical trial of the impact of melatonin on influenza vaccine: Outcomes from the melatonin and vaccine response immunity and chronobiology study (MAVRICS).

Vaccine immunogenicity is affected by a variety of factors. Melatonin has been reported to affect immune responses to vaccines and infection. This was a randomized open-label trial - in which adults scheduled to receive the influenza vaccine were randomized to 5 mg melatonin or control to evaluate the effect of post-vaccination melatonin on humoral (hemagglutination-inhibition assays, HAI) and cellular (FluoroSpot) vaccine-specific cytokine responses 14-21 days post-vaccination.

AMA1 and CSP antigen diversity in parasite isolates from southern Ghana.

Introduction: Diversity in malarial antigens is an immune evasion mechanism that gives malaria parasites an edge over the host. Immune responses against one variant of a polymorphic antigen are usually not fully effective against other variants due to altered epitopes. This study aimed to evaluate diversity in the Plasmodium falciparum antigens apical membrane antigen 1 (PfAMA1) and circumsporozoite protein (PfCSP) from circulating parasites in a malaria-endemic community in southern Ghana and to determine the effects of polymorphisms on antibody response specificity.

Induction of antigen specific intrahepatic CD8+ T cell responses by a secreted heat shock protein based gp96-Ig-PfCA malaria vaccine.

Introduction: A highly efficacious and durable vaccine against malaria is an essential tool for global malaria eradication. One of the promising strategies to develop such a vaccine is to induce robust CD8+ T cell mediated immunity against malaria liver-stage parasites.

Methods: Here we describe a novel malaria vaccine platform based on a secreted form of the heat shock protein, gp96-immunoglobulin, (gp96-Ig) to induce malaria antigen specific, memory CD8+ T cells.

Immunodominant T cell peptides from four candidate malarial antigens as biomarkers of protective immunity against malaria.

A malaria vaccine with high efficacy and capable of inducing sterile immunity against malaria within genetically diverse populations is urgently needed to complement ongoing disease control and elimination efforts. Parasite-specific IFN-γ and granzyme B-secreting CD8 + T cells have been identified as key mediators of protection and the rapid identification of malaria antigen targets that elicit these responses will fast-track the development of simpler, cost-effective interventions. This study extends our previous work which used peripheral blood mononuclear cells (PBMCs) from adults with life-long exposure to malaria parasites to identify immunodominant antigen-specific peptide pools composed of overlapping 15mer sequences spanning full length proteins of four malarial antigens.

In vitro production of infectious Plasmodium falciparum sporozoites.

An effective vaccine is needed for the prevention and elimination of malaria. The only immunogens that have been shown to have a protective efficacy of more than 90% against human malaria are Plasmodium falciparum (Pf) sporozoites (PfSPZ) manufactured in mosquitoes (mPfSPZ). The ability to produce PfSPZ in vitro (iPfSPZ) without mosquitoes would substantially enhance the production of PfSPZ vaccines and mosquito-stage malaria research, but this ability is lacking.